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ABCs Population

The surveillance areas represent 22,392,985 persons and 317,976 live births. Source: U.S. Bureau of the Census, 1998; National Center for Health Statistics Vital Records, 1996.

ABCs Case Definition

Invasive group B streptococcal disease: isolation of group B streptococcus from a normally sterile site in a resident of a surveillance area in 1998. Early-onset cases occur at <7 days of age and late-onset occur between 7 and 90 days of age.

ABCs Methodology

Project personnel communicated at least monthly with contacts in all microbiology laboratories serving acute care hospitals in their area to identify cases. Standardized case report forms that include information on demographic characteristics, clinical syndrome, and outcome of illness were completed for each identified case. Regular laboratory audits assess completeness of active surveillance and detect additional cases.

Rates of invasive group B streptococcal disease were calculated using U.S. Bureau of the Census postcensal population estimates for 1998. Rates of early-onset and late -onset group B streptococcal disease were calculated using natality data for 1996. For national projections of cases, race- and age-specific rates of disease were applied from the aggregate surveillance area to the age and racial distribution of the 1998 U. S. population or 1996 live births. Cases with unknown race were distributed by area based on reported race distribution for known cases within the eight age categories.